Brake for electric motors



v Oct. 21, 1947. c, E, MEYERHOgFER 2,429,325

BRAKE FOR ELECTRIC MOTORS Filed June 11, 1943 INVEN TOR. far! 5 fieyzr/zoz/er BYMQMMQMW Patented Oct. 21, 1947 BRAKE FOR ELECTRIC MOTORS (Jar! E. Meyerhoefer, Brooklyn N. Y., assignor to E., A. Laboratories, Ind, Brooklyn, N. Y., a cor poration of New York Application June 11, 1943,, Serial No. 490,408

1 Claim. 1

This invention relates to a structurally and functionally improved lamp and in its more spe cific aspects aims to provide a mechanism of this character which may be associated with aircraft; the disclosure of the present: application pre senting improvements over those embodied in my prior application, Serial Number 450,561, filed in the United States Patent Office on July 11, 1942, now Patent No. 2,362,116,, granted November '7, 1944 and application Serial Number 479,329 of John R. Aufiero, filedin: the United: States. Patent Ofiice on March 1'6, 1943, now Patent No. 2,390,634, granted December 11, 1945.

It is an object or the invention to furnish a mechanism of this type and by means of which desired circuits may readily be broken and reestablished", as. units of. the assembly are removed and. replaced therein.

A further: object is that. of furnishing a lamp structure. including a. motor drive and which structure will, remain immobilized in any position to which it is adjusted; such structure, however, being readily capable of having its position shifted. at the. will of the operator.

Another object. is. that. of providing a mechanism contained in. a substantially sealed structure such that the entrance. of water or foreign elements into the motor; parts will be. virtually precluded.

With. these and further objects in mind, referonce is had to the attached sheet of drawings illustrating one practical embodiment of the in vention, and in which:

Fig. 1 is a fragmentary view of a portion of a lamp housing with a drive mechanism associated therewith;

Fig. 2 is a transverse sectional view taken. along the lines 2.Z and in the direction of the arrows as indicated in Fig. l; and

Fig, 3. is a sectional view taken along the. lines 3-3 and in the. direction of the arrows as indicated in Fig. 2..

In thesev views. the. reference. numeral 5 indicates a. housing. within which a shell 6. is re tractable; The. latter is. pivotally supported as at i with respect. to acasing it. The shell mounts a light unit of which the lens 9 has been indicated in Fig. 1.

As also indicated in this figure, a suitably encased motor .3. is. disposed adjacent the casing 8 and serves to drive a sprocket or pinion II. The teeth of this element mesh with a gear 12 to which is coupled a gear I3, in turn meshing with the teeth of an arcuate rack 14. A socket I5 provides for electrical connection and a brush and 2 switch structure generally indicated at l6 serves to assure proper energization of a filament of the lamp, all as taught in my aforeidentified applications.

In'the structures disclosed in these previous cases, some difiicul-ty has been experienced in connection with the removal of the motor from and association of the latter with the general lamp-assembly. This has occurred when, for example; the motor has had to be renewed or replaced. More particularly, the difficulty has been experienced that the leads coupling the motor have had tobe broken and subsequently resoldered. By the teachings of the present invention, this difficulty is overcome.

In this connection, reference is had to Fig. 2, in which the reference numeral i1 indicates a base preferably formed of dielectric material and interposed between the motor In and the casing portion 8. As will be appreciated from an inspection of this view, certain details of the gear assembly and the reduction drive has been somewhat schematically illustrated in Fig. 1; this being for the purpose of simplifying the illustration. To thus secure the encased motor to the casing 8 with the base I! interposed between the. same, bolts. I have been conveniently employed'. These bolts: obviously serve as a medium permitting ofready dismounting of the parts and a coupling of the same such that relative movements between the several portions are normally precluded. Also in accordance with the teachings of the present invention contacts l9. may be'insulatedly mounted on the base of the motor i0 and connected by leads to properly energize the motor parts when these contacts are in electrical connection with a source of: current supply. Such a source is furnished from the; socket I15 through leads 23 to contacts The latter are insulated from the casing 8- but preferably exposed on the exterior face of the. same. Carried by the base I! are springpressed connecting elements including shells 22 and plungers 23 a spring 24 being in each instance provided to normally project the plunger.

Obviously, these assemblies or their functional equivalent are associated with the base H in line with the contacts l9 and 2-1 when the casing 8, encased motor H and the exposed base I! are properly disposed with respect to each other. It follows that a mechanic will have no difficulty in simply applying the base I! to the casing 8 and thereupon mounting the encased motor In upon the base l1. As afore brought out, the position of the several parts is preferably maintained 3 by the bolts l8. As the parts are tightened, it is apparent that the plungers 23 will engage certain of the contacts 21 while the housing 22 will engage corresponding contact 19. Thus, as the motor is mounted in position, the electrical connection will be automatically established by the mechanic and without any conscious effort on his part. Accordingly, there will be no problem of breaking this connection as the parts are dis mounted or re-soldering or otherwise re-establishing the same upon the parts being assembled.

Certain difficulties have also been heretofore experienced in providing a definitely operating mechanism whereby the parts will be locked in position at the will of the pilot or other operator. The present mechanism furnishes a unit achieving this functional result and which unit will occupy a minimum amount of space and at the same time operate with maximum efficiency.

Referring especially to Figs. 2 and 3, it will be seen that the reference numeral 25 indicates a plate or stamping which is pivotally mounted as at 28. This plate carries an armature portion 21 and has cooperating with it springs 28 mounted upon pins extending from the field 29 of the motor. The outer end of the plate lies adjacent the armature 32 of the motor and carries a snubber block 30 retained in position by a plate 3|. The block 30 may be formed of rubber or any similar or suitable material and as shown especially in Fig. 3 has its face conforming to the configuration of the armature.

With the parts in positions shown in Fig. 2, the springs 28 press downwardly against the plate 25. Accordingly, the latter tends to rock around its pivots 26. Therefore, the snubber block 30 is brought into intimate contact with the face of the armature and prevents the latter from turning. As soon as the motor is energized, however, the fiow of current through the coil of the latter will cause the armature 21 to be attracted. This will have the effect of moving the adjacent end of the plate 25 towards the field of the motor and compressing the spring. Accordingly, the plate will rock around its pivots 26 and the block 30 will be moved away from and spaced With respect to the armature. The latter will now be free to rotate. With the flow of current through the parts, such rotation will immediately follow and continue until the fiow of current is interrupted. Thereupon, the brake effect exerted by the snubber will immediately be re-established. Consequently, with the relatively high value of the reduction gearing included in this assembly of the parts, there will be no danger of any of the mechanism shifting from the position to which it has been adjusted.

It will also be appreciated that as a consequence of employing the base l1, it is feasible to enclose the mechanism contained in the latter in a lubricant and to provide a water-tight seal of the oil type between the space and the motor casing. Accordingly, it will be almost impossible for water to enter into the motor casing under any circumstances. Therefore, the latter will continue to function under substantially all conditions. Obviously, this feature is of value when the present structure is employed in connection with any vehicle or mounting which is exposed to the action of the elements. It is of especial value in the case of airplanes, and particularly seaplanes. As will be understood, in both such installations the lamps are almost invariably projected during a night landing and thus water (in the case of sea-planes, in the form of salt spray) is free to impinge upon the lamp, its shell and within the housing. Generally, it is not feasible to provide a water-tight fit which will prevent moisture from moving along the arcuate rack I 4 and into engagement with the pinion ll. Also, this water will come in contact with the exterior of the motor casing. However, by the present construction, it will not enter the latter.

From the foregoing, it will be understood that among others the several objects of the invention as specifically aforenoted are achieved. Obviously, numerous changes in construction and rearrangements of the parts might be resorted to without departing from the spirit of the invention as defined by the claim.

I claim:

In an electric motor having an armature formed with a plurality of poles having closely spaced extremities which collectively define a substantially cylindrical wall surface of appreciable area, a field magnet having leg portions extending along each side of said armature and a field coil for magnetizing said field magnet; a brake structure comprising an open frame having side members overlying the respective field magnet leg portions; a brake block secured to one end of said brake frame and overlying said substantially cylindrical armature wall surface; a magnetizable member secured to the opposite end of said brake frame and extending transversely above said field magnet adjacent the field coil thereof; means disposed on the respective side members of said brake frame intermediate the ends thereof for pivotally mounting said brake frame for rotation at right angles to the plane of said armature and said field coil; and spring means extending from each field magnet leg portion and bearing against the respective side members of said brake frame to rotate the frame to bring the brake block thereof normally into braking engagement with said armature wall surface, said spring means yieldin upon magnetization of said field coil and resultant attraction of said magnetizable brake member towards said field coil to permit rotation of said brake frame in a direction which disengages the brake block from said armature surface.

CARL E. MEYERHOEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,437,421 Holliday Dec. 5, 1922 2,186,674 Hildebrand et al Jan. 9, 1940 2,222,252 Cochran et al. Nov. 19, 1940 2,298,155 Perkins Oct. 6, 1942 2,323,945 Strauss et al. July 13, 1943 521,138 Crowdus June 5, 1894 2,162,161 Cotant June 13, 1939 2,144,416 Nevinger Jan. 17, 1939 1,539,068 Brockett May 26, 1925 2,340,052 Grimes Jan. 25, 1944 515,755 Dunn Mar. 6, 1894 

